The present invention relates to semiconductor package manufacturing and semiconductor packages.
To fabricate a semiconductor package typically the components thereof must be treated. For example, in U.S. application Ser. No. 11/138,141, assigned to the assignee of the present invention, a method of fabricating a package is disclosed in which the front surface of the semiconductor die is subjected to a multi-step process whereby it receives a passivation body before the die is assembled in a conductive can.
In a process according to the present invention, a drop on demand deposition technique is used to form a body on a semiconductor package component. A process according to the present invention can be used to form, for example, a passivation body on a surface of a semiconductor die, a dielectric body on a lead frame portion of a semiconductor package, and so on.
A major advantage of drop on demand deposition is the reduction in process steps. The following is a comparison of a prior art process to a typical drop on demand process:
Prior ArtDrop on DemandSpin on materialPrint materialDry volatiles from materialDry materialUV exposeCure materialDevelop materialCure material
The prior art method is disadvantageous because: a) it requires more material than required for the final structure; b) the material has to be developed, which means there are significant costs associated with the chemistry and the waste produced; c) additional steps are required; d) photo-initiator systems for imaging can weaken the performance of the materials; e) damage or contamination on the photo tool can result in openings in the passivation which may present problems.
On the other hand, drop on demand deposition: reduces waste; reduces the number of steps; can treat surfaces that are not flat; can vary the thickness across the image in a single pass; is not as susceptible to contamination defects as the prior art.
Drop on Demand is known to be used in:
Component part marking;
Depositing dielectrics on plasma display panels;
Printed circuit board production and marking;
Fine geometry circuit track printing using precious and semi-precious metals.
However, a search has not revealed drop on demand deposition used for fabricating a semiconductor package component such as a semiconductor die, lead frame or the like.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.